Re: [Boost-users] [lexical-cast] double not converted as it is to a string

From: Tom Bachmann (e_mc_h2_at_[hidden])
Date: 2007-04-01 05:03:56

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Digvijoy Chatterjee schrieb:
> ...
> here is a simple program,
> int main() {
> double  d=76.32;
> std::string s = boost::lexical_cast<std::string>(d);
> cout << s << endl;
> }
> 
> output
> 76.319999999...
> 
> a) am i doing something wrong ??

I don't think so.

> b) if this is not wrong s this standard behavior ??
> 

I'd say so. Due to the binary representation not all numbers with a
representation of a fixed amount of digits in our decimal system have
such a representation in the computer. Lexical_cast internally uses
standard streams, if they don't correct such things (and I don't know of
any implemementation that'd do so), your output will look garbaged. Try
adding std::cout << d << std::endl.
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